IMO a good idea would be to vary the featured character among all characters, not just the 3s. 3s still get their 50% boost, but say 2* gets 100% feature boost, and 1* gets 150%.
I think it might help the 1 and 2* players a bit, since I see a lot of 3* rosters that have shed their 1s all together. I don’t know that a level 125 Yelena could actually do anything of worth against the big 3*s, but it’d be better overall if they didn’t have characters that are effectively ISO covers, and it would give lower level players at least a chance once in a while to have a 3rd member of PVP that isn’t a generic low-level 1-color.